Walkerton is a small town in southwestern Ontario. On Tuesday last, May, 23, 2000, the town administration anounced that its water supply was contaminated with E. coli, variant O157:H7, the most virulent strain. It couses hemolytic uremic symdrome, recognized by its most obvious symptom--bloody diarrhea.

The chronology of the outbreak is disputed, and under outside police investigation, but seems to be this:

The laboratory that tested the drinking water of Walkerton was not certified for E. coli screening, A & L Canada Laboratories East Inc., a franchisee of a U.S.-based chain, apparantly sent test results to Walkerton on Thursday, May 18, showing E. coli contamination. Nothing was done.

By the next day, Friday, May 19, the medical officer of health, Dr. Murray McQuigge, a Harvard-trained public health specialist, received reports of the first cases of bloody diarrhea. He asked the Public Utilities Commission if the water was contaminated. He was told no.

This sceanario repeated on Saturday, May 20, and on Sunday, May 21, each day bringing more reports of stricken people to the medical officer of health. Each day he confronted the municipal authoritities. Each day he was told the water was safe.

On Sunday, May 21, Dr. McQuigge did what he could on his own authority--he issued a boil water order.

On Tuesday, May 23, the municipality admitted that there was an outbreak. But by then, five people had died--including children and seniors. Walkerton is a small town, and is unable to treat so many people fallen ill in so short a time. A call went out for medical personnel to assist, and the sickest were transported to London, Ontario.

Schools and day care centers were closed, and parents were being urged to have their children’s blood tested every second day for E. coli. The incubation period for this disease is 5 - 7 days, and the middle of the week was about that many days after a heavy rain storm which had, apparantly, washed the E. coli bacteria into the well from which the town draws its water supply. This strain of E. coli orignates in animals.

As of Saturday, May 27, 2000, the statistics were over 1,000 people afflicted, many children and seniors, whose immune systems are at risk, 4 children on Kidney-dialysis; more are expected to die.

It is the worst outbreak of E. coli contamination in Canadian history--and it's not yet over.